1. Field of the Invention
This invention relates to a molded plastic tamper-indicating plastic closure, which closure is provided with a tamper-indicating band at the bottom marginal portion thereof with integrally formed tamper-indicating wings extending inwardly from such tamper-indicating band, and this invention further relates to a molding apparatus in which the closure is removed from the core pin of the apparatus by an unscrewing action.
2. Description of the Prior Art
As is known in the prior art, in the molding of a plastic closure for a beverage or other container, it is known that the closure may be removed from the core pin on which it is molded either by a stripping action or by an unscrewing action. While the removal of the closure by a stripping action is generally a less expensive manufacturing procedure, greater resistance to stripping of the closure on the threaded finish portion of the container to which it is to be applied, both during the initial application of the closure to the container or during any subsequent reapplication of the closure to the container, is obtained by unscrewing the closure from the molding equipment core pin, since the closure thread profile which is necessary to permit stripping of the closure from the molding equipment core pin will also make the closure more subject to stripping on the container finish.
Many types of molded plastic closures for beverage containers and for other types of containers are advantageously provided with tamper-indicating bands, to provide a visually detectable indication to the consumer, upon the first opening of the container, of any prior opening or attempted opening of the container. Many such tamper-indicating closure designs require a heat-shrinking or other operation, subsequent to the application of the closure to the container, to provide or ensure that the package containing such closure does have suitable tamper-indicating characteristics. See, for example, U.S. Pat. No. 4,206,851 (E. M. Ostrowsky) which describes a molded plastic tamper-indicating closure in which the tamper-indicating characteristics of the closure are provided by an annular band which depends from the underside of the closure skirt and which is shrunken in diameter by a heating operation to engage the underside of a flange on the finish of the container, a construction which causes such tamper-indicating band to fracture from the skirt of the closure upon the unscrewing of the closure. However, it is frequently desired to avoid the need for a subsequent heat-shrinking or other secondary processing operation on a closure once it has been applied to a filled container to create or to ensure proper tamper-indicating characteristics upon the removal or attempted removal of the closure from the container. U.S. Pat. No. 4,407,422 (S. L. Wilde, et al.) discloses a molded plastic, tamper-indicating closure which, in the embodiment of FIG. 4, derives its tamper-indicating characteristics mechanically, without the need for any heat shrinking or other subsequent processing operation, from a plurality of non-radially extending fingers or wings which are attached to the inside of the tamper-indicating band at the margin or bottom of the closure skirt. However, heretofore it has not been possible to manufacture a molded plastic, tamper-indicating closure of the type illustrated in the aforesaid U.S. Pat. No. 4,407,422 except by a stripping operation, due to interference in the closure molding tooling between the tamper-indicating fingers or wings and the portion of the tooling that is used to form such tamper-indicating fingers or wings.